


Unfamiliar Waters

by Hyrulehalfbreed



Category: Iron Man (Movies), The Avengers (Marvel) - All Media Types, Thor (Movies)
Genre: Deep Sea Mer!Loki, Happy Ending, M/M, MerMay, Plot What Plot/Porn Without Plot, Predator/Prey, Sea Monsters, Tentacles, Top Tony Stark, Younger!Loki, mermens, older!Tony, volcanic vent Mer!Tony
Language: English
Status: Completed
Published: 2019-07-13
Updated: 2019-07-13
Packaged: 2020-06-27 10:43:51
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 9,015
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19789240
Author URL: https://archiveofourown.org/users/Hyrulehalfbreed/pseuds/Hyrulehalfbreed
Summary: Living in isolation among the volcanic vents was a rather boring life. Okay, more than boring it’s scale tearing mundane. When something different invades his waters however, Tony realizes that perhaps he should be more careful about what he wishes for.





	Unfamiliar Waters

Tony was relaxing, his eyes half closed as he stretched out while enjoying the calm sounds around him: the hissing of the vents that spouted water that had been heated by the magma flows that existed just meters below the rock, coral, and sand he reclined on. Different crustaceans skittered as their spindly legs crawled about. Fish, sea slugs, and the odd octopus would venture close, but none stayed still for long. It was late in the morning, and he had yet to obtain the motivation to move more than he already achieved with squeezing out of his den and finding a place to sunbathe where the natural light shined through the water unimpeded. 

It was just another day of quiet self-imposed isolation, a well known and mostly accepted course of action among the pod he left so long ago.

He had gone in the dead of night, preventing those that he was actually fond of from following him. They did not need to lose their home and friends chasing after a faulty belief that a normal life could exist in the same waters as Tony.

He was free to do as he wished in his territory, but the cycle of monotony was becoming almost maddening as it stretched past two decades now. Still, it was far better this way. _Safer_ for him, and others. 

Today was just another cycle of all his previous days: sunbathe, swim to the corals, eat, patrol, tinker with things he found in the sand dropped by the great floats that passed above; and then sleep. Nothing exciting.

Or Tony had believed that it was before a scent reached his nose and his head snapped up. Something was there, something new. He frowned and pushed off with his golden scaled tail to go and search for what had breached his territory as he caught the blood in the water. 

With swift beats of his tail he swam through the salty waters, entering the cooler temperatures that were encompassing his territory. More life springing up around him, more branching, tiered corals, swaying kelp and anemones, giant clams, small sharks, peering eels, and numerous fluttering fish. The last of these fauna were the ones that were fleeing. 

That was when Tony got mad. Not only was there something in _his_ area, but that something was scaring _his_ food! No one touched his stuff, no one came out here either. Anger fueling his muscles. He began swimming faster to find the source, zeroing in on a stranger he'd never seen before with a shout.

"Hey!"

The figure froze at the sound of an unfamiliar voice. Perhaps he had thought that there would be no other mers in the area as the water here was sweltering to most as only a few kilometers away magna oozed from the volcanic vents that ruptured this shallower portion of the ocean floor. But looking at the creature that held a struggling parrotfish in his claws… 

Tony was starting to rethink whether the other might be a mer at all. 

Or if he was one, it was a species he had never seen before. 

Long green tail that looked darker than kelp to almost black in color as it shifted in the water. The rays of sunlight that pierced the ocean didn’t seem to be reflecting off its scales, instead being absorbed. The tail was more eel like, smooth and uniform in shape as it draped after the torso. Two, long swooping spiny pelvic fins sat just under where skin gave way to scales. These fins, while mostly folded down now, looked to be made to snap open in an instant. Which would result in a quick stop or achieving faster turns in the water. 

The length of the tail was also staggering, at least five times that of the rest of the body. 

There was also the skin of the stranger, it was _blue_. A deeper blue than the water around them, more like a Blue Tang. Raised lighter colored lines traced symmetrical patterns across the arms, chest, waist, neck, and face of the invader. If he turned around, Tony felt that most likely his back too would be covered in these markings. Long black hair that reached his shoulders drifted in the current, which revealed from time to time the pointed, fin edged ears on either side of his head. 

Sprouting from the other’s skull were horns. No, no, not like the bright yellow, blue polka dotted, Longhorn cowfish. Nor were they like the fleshy nose-like protrusion that belonged to some members of the Tang family known as Unicornfish. These were bony, rigid structures which seemed to be glowing a faint gold color, the light drawing in curious fish that did not know better than to stay away from the strange, new thing that was quickly turning out to be an unfamiliar predator. The horns sprouted further up on the other’s forehead, rising high in a graceful curve before the tips angled downwards like they could pierce through the ocean floor. 

The last starting feature were the eyes, red in color and glaring back at the shorter mer as he bared his sharp needle-like teeth. Releasing the fish, the poor creature swayed sideways, drifting towards the ocean floor and not about to recover as the predator was apparently smart, piercing his claws into the fish’s swim bladder to cripple it. 

Obviously, now the stranger had… bigger fish to fry as it were. 

“I’m accustomed to my prey coming to me, but not to such a degree.” A smooth voice answered, but there was a youthfulness to it that contrasted the longer length of his body when compared to the native mer. Going by his tone, it seemed that he could even be younger than the bright tailed one. However, Tony couldn’t ponder on it for long, as those words were all the warning that the stranger gave before he darted forward in the water, fangs and claws bared. 

Tony hissed, treading his water as the spikes on his back flared out and the temperature rose in his scales, causing the once purely gold scales to glint with shades of red and orange. He let the other come to him, doubting true injury would come his way as it hadn’t in so many, many years. "Alright Nar-, no, Biwhal, just you _try_. You can’t hurt me." 

He watched the trespasser curious as he was angry. Tony might not first appear as the most threatening thing in the sea, what with his own tail only slightly longer than a time and a half of his torso. Still there were long red spines that decorated his back that he could flare to seem bigger and scare away sharks. His tail was a golden color that reflected the sun when it hit just right, he often thought of tropical fish when his kind swam and danced in the water. 

Flashy and colorful.

The stranger veered off course at the last second, speeding by the short tailed mer and instead began circling. Possibly put off by the other's cockiness. The charge hadn't been a bluff, it seemed that he had completely intended to go through with it, but at the sight of the other's sail; he spooked. His own inexperience showing, along with his intellect. 

Some fish, slugs, and other creatures had unique colors, patterns, and features to warn that they were venomous. The lionfish and sea snakes had distinctive patterns that warned loud and clear that they were not to be fucked with. It was better to be cautious than to leap into something that could sting or bite back to a degree that was not easily recovered from.

The tall sail was something that the other seemed to have never encountered before from the way that he was eyeing the specialized dorsal fin. The film that stretched between each spine a brilliant light blue in color crossed with ripples of orange. It was quite the display. So many colors that most creatures had only two reactions when their eyes were met with the onslaught: backing off, or urging closer by curiosity. 

The stranger seemed to be stuck between the two, circling Tony with narrowed eyes; sizing him up. Then, without warning, he darted back in. Whizzing back to Tony’s front, long tail wrapping around that shorter one, while a hand dug into the other's shoulder and the other upon his upper arm. An obvious attempt to immobilize and try to drive his prey towards the ocean floor. 

Tony hissed and grappled at the unknown creature, his body temperature rising as he closed his eyes starting to feel _hot_. He did not feel bad about trying to get the other to let go of him by using whatever tricks he had. He felt the water growing warmer around them as he struggled, focusing on pushing the heat into his hands and tail to buck the other off. 

The heat was sudden and scalding, as was the yelp followed by the release of the native mer as the other scrambled to get away from the unfamiliar burning sensation. The blue skinned mer was wincing as he put over a dozen meters of distance between them. Light purple blisters were scattered across him from the waist up. His expression confused, obviously not expecting this turn of events. 

His meal turning into a threat.

Tony swam back up, ignoring his own collection of scratches and forming bruises. They stared each other down, red eyes clashing with golden brown, before Tony swiped his tail to return to his home. Hoping the strange creature learned his lesson and would stay away.

Gee, wasn’t that just a _wonderful_ way to start his day, Tony thought with a sigh as he moved back through the smaller reefs. He caught a few fish to eat for himself while still watching the waters with curious, slightly panicked eyes. While his mind may have slightly calmed, his body was still tense and ready for a fight as the adrenaline pumped through his veins. 

The spines on his back were still showing just in case, even if it made him feel a little ridiculous.

Like he was a seabird that had its feathers ruffled.

Unknown to the golden tailed mer, in the limited shadows that the rare reef provided in the hot waters, the stranger watched. He should have left when the other was obviously not a food source and would defend his territory, but still he lingered. Curious and confused about what had just occurred. This sense of wonder was one of the reasons that he was far from what he once considered his natural environment to begin with. 

That sail was entrancing to watch as it swayed in the water with its owner. Actually, all of the other was fascinating: molten with colors of red, gold, and a shimmering blue. Colors that were so very rare where he had risen from, particularly in such a large supply. Gold, it radiated from his own horns when he was hunting. Tempting food from the darkness to investigate the color and light. If it was a dangerous creature, the light would be cut off and he would hide himself away until it moved on then he’d try the trick again. 

On this mer, his scales stayed the vibrant colors and flashed like an irresistible lure that refused to be ignored or forgotten. So, despite the temperature rising steadily higher the longer he followed, he couldn't make himself move on to saltier waters. 

Tony had eased eventually, going back to swimming the waters easily as his spines lowered and he hunted. His diet varied from which part of his territory he frequented. Crustaceans, octopi, certain types of slugs, mussels, clams, and different plants. Usually whatever small collection of critters that he could snatch from the reefs or dig out of the sands were on his menu. Still as he filled his belly, Tony couldn’t help his thoughts from turning back to the creature. Wondering if he would return, where he could have originated from. 

Time passed slowly, the longer mer constantly watching. After the other's spines lowered he waited, still. His blisters healing slowly, the sting of them a passing trifle in the back of his mind. It was only once he was sure the other mer was relaxed that he darted out again from the cover of a reef. Claws looking for purchase as he struck the golden tailed mer in the side.

Tony hissed, his body heating once more as his spines flared, catching the sight of red blood trailing through the water; this time his own. He lashed out at the attacker, surprised to find that it was the blue mer once more. 

"Oh come on! _No!_ " He groaned as he managed to push off of him. Demanding as he held his bleeding side, his eyes closed tight against the pain. Tony burning this guy once had seemingly not been enough: he had come back for fucking seconds.

"Who are you!? Why are you even here?"

The stranger had hissed at the feeling of the other's flesh rising in temperature, releasing his hold before he could get burnt too badly this time. Still it confirmed that the last incident hadn’t been a fluke, the heat was real. Speeding to put a bit of distance between them once more, he didn't go back into hiding. Instead he drifted, head cocked to the side as he tasted the other's blood in the water. A different flavor than he was used to, spicier if he had to name it. At the question, he appeared to decide that it couldn't hurt to answer. He had his own inquiries he’d like acknowledged after all. 

"I am Loki, and I am burdened with drifting." 

Tony narrowed his eyes, holding his side as he took in _Loki's_ appearance and swallowed. Okay, so Loki was freakishly intimidating and otherworldly now that he was getting more of a chance to look at him while not trying to slice each other to ribbons. 

"Right, well I'm Tony. Now that we got niceties out of the way, though I’m really doubtin’ you know the meaning of that word... Why have you attacked me? I've done no wrong to you." 

"Because you resemble prey," Loki answered with a casual shrug of his shoulders. With the blisters along his tail, arms, and hands, he assumed that they were relatively even now. He circled the other again, obviously curious with a different hunger lighting his eyes than when he first encountered Tony. Before it was a carnal hunger to fill his ever hungry stomach, now it was more of an impotent desire for knowledge. To work out the puzzle that he was presented with. "But the ones from before lacked that sail on their backs, nor were they hot to the touch... Or at least not to the degree you are." 

Tony frowned, not sure how to take the fact that he was dealing with a person that believed mer was an acceptable menu item. Sure, Loki had said something along those lines when they first met, but he had thought that it was more of a front. Only an attempt to scare Tony away and into giving up his territory. It was something Tony was going to have to shelve for now.

“You won't find another like me either. And what about you? I haven’t seen any kind like yourself. You're very, well, large." He took in all of Loki's long tail and looked back to his face to add, "and blue."

"I am a Jotun, I am from..." Loki’s brows pinched as he tried to think of how to explain the abyss he had risen from. Not many from above dared to visit there, those that did were usually swiftly eaten by his kind or by the many other predators that stalked the dark, frigid waters. "The very deep, I suppose." 

Despite how it made his nose wrinkle in distaste, he admitted while drifting just a little closer, "I’m rather small for my species actually."

Tony felt his eyes widen comically, but really could anyone blame him? All he knew was that he was never going to go into any ocean chasms. Nope, hard pass on that, he’d rather chew on a conch shell. That did beg the question though, "What brings you here? My food? This is _my_ home, not yours. Quite rude barging in and stealing."

"Are you going to _make_ me leave?" Loki asked, looking amused at the idea. While he might not be able to eat the other, he didn't think that Tony could actually chase him off. "I've been following the currents where they take me. It's rather boring further below, and most would rather gnaw on you instead of exchanging any riveting conversation."

Loki’s kind was even prone to cannibalism if the mood caught them. No, the only time they enjoyed each other's company was to breed, raising their young, and perhaps to take down larger prey before squabbling over it. 

It was rather dull. 

Loki was clever, but his size didn't exactly endear him to anyone. He was young so he decided to try his hand in different waters.There had to be more than the desperate scramble for survival and darkness that he had known. Unfortunately, it seemed that this new mer wasn’t exactly willing to engage with him either. 

Tony huffed and puffed his chest out, sail still high. "Well then move on. Just keep swimming and all that. Cause, _again_ , this is my home, not like you want to stay here with a beast that'll hurt you." With a flick of his fins he moved through the water, putting more distance between them again as he summoned the fire in his veins, his scales shifting in color like light dancing off the waves above them at sunset. "I live alone, that is how it is."

Loki pursed his lips at the dismissal. He was used to it, many of his kind ignored him for the fact that they thought he wouldn't even make for a good snack. Still, it irked him. He darted up to block the other's way, "You call yourself a beast when I am the one that tried to eat you? After I have admitted to having devoured those... those-." 

He flapped his hand in the water, trying to remember what the mers of the coral reefs called themselves. They looked like Tony with the absence of the great sail on his back, where typically bulkier and louder too, "Aesir, that's it." 

Tony huffed as he watched Loki carefully. The other was quick and he could already tell that he wouldn’t be able to out swim him. His stomach roiled at the mental image of Loki sinking his teeth into limbs much like his own. Yet it was part of the cycle of life. Tony could tell from the way that Loki was built that he was indeed meant to eat large creatures, mer sized or bigger. Needed such large quantities of meat to sustain such a strong predatory body. Did Tony feel bad for the fish he ate? No. Did they talk back to him? Typically, no. Would he still eat them if they did… Probably. Survival. All beings did desperate things for survival. That was why Tony was basically run off by his pod. The other would come to the same conclusion as all the rest soon enough. 

"I am alone. The only of my kind, born with a curse. The others hated me, called me a beast because of my... Nature." He looked to his hands and then back to Loki. "I don’t know your species, you're just a new asshole stealing my fish."

"Like fish are in _such_ short supply," the longer mer answered with a roll of his eyes, though he was still gazing at the other curiously. Not at all put off by Tony’s hostility, however the fins surrounding his ears did fold back as he looked at those tanned hands. Those blisters on his own did not need new companions. 

Still Loki was close now, almost able to touch, but kept his arms crossed in front of him in a show he didn't intend to make another grab, at least for now. "You're nature, now what do you mean by that exactly?"

Tony found himself calming at the questions, his spikes only going down slightly. The exchange of knowledge and words, oh he missed it. "The heat in my body, none of them dare come near me, though I can control my anger and my heat. They didn’t believe I wouldn't hurt them, regardless of how many times I _swore_ that I was harmless. Proved that I could be an aid, rather than a threat."

Rolling the words through his mind, Loki could come to several conclusions from what was said and what wasn’t. One, Tony was lonely, from a species that were social and most likely lived in larger family units. To be removed from his kind was akin to cutting off a fin. Two, Tony had a temper, which wasn't that surprising, it almost seemed like magma made of fury boiled just under sun exposed skin. That Tony could control his strange abilities, but was never given the chance to prove it.

Three, Loki desperately wanted to test the theory. 

His hands moved quickly, lacing and interlocking their fingers together. A full body shudder rolled up the deep sea mer's frame as the other indeed felt warm and not scalding like before, but there was a simmering heat there that had been absent in the cold depths that continued to radiate from his own blue flesh. 

Tony took a sharp breath as Loki held his hand, his cool skin was- welcoming to the touch, but still he frowned softly. "Are you so wise to trust I won’t burn you? I have no reason to trust that you won’t try to eat me again..."

"For that reason we can come to an agreement, can we not? Both of us unaccepted and dangerous," Loki answered, much more invested in examining Tony as he brought their intertwined hands to eye level so he could take in the differences between them. 

The color was the most obvious, followed by the length of the nails that covered Loki's hands compared to Tony. Black, longer, and slightly curved so it would be that much more impossible for his prey to escape him without injuring itself further. Then there was the webbing between their fingers. Tony's only extended up to the first knuckle of each digit and was tight between them. Loki's, on the other hand, had webbing that extended to the second knuckle of each finger, far more loose extra webbing covered in black and white scales. 

This close, Tony was able to see now that there were small black scales dotting the edges of Loki’s eyes, along with the more snake-like pupils in those red orbs. Tony’s were more round and he had a splattering of red scales around his gills. 

"Interesting."

Tony nodded in agreement and let himself get closer to Loki. Watching, no, studying him with the same amount of fascination he was getting. He hummed softly as his tail tread near the darker one. "You’re pretty strange too. What’s your name again? What do I call you?"

"I've been called worse things than that," the other answered, drawing the back of one claw against the webbing that existed between Tony's thumb and forefinger. This flap of skin was absent on the longer mer's own hands. His tail swayed beside Tony's now, his long pelvic fins shifting slightly to keep his position in the water. 

"I am called Loki, but what you call me in your company, I cannot yet fathom."

Tony nodded as he moved forward even more as he studied Loki’s face. After going so long without physical contact with another… Not only that but someone that did not shy away from or fear his curse, Tony was desperate to keep the touch and perhaps even embrace more. He licked his lips, tasting the other’s scent in the water. "So are you just passing by? Or do you intend to stay?"

Loki's lips twitched upward in amusement, "My, how your tune has changed. You were trying to oust me from your territory just a short time ago." His ruby eyes watched the other's tongue, trying to ignore the rush that flooded through his body. Tony didn't intend to eat him, or at least gave no inclination to, so the action shouldn't inspire the fear that it usually did coming from another Jotnar. "I grew bored of the deep. My kind usually does not stray this far up, the light is harsh on our eyes and the water uncomfortably warm. Not much prey outside of other mers, sharks, and mammals large enough to sustain us." 

Tony tipped his head watching Loki's eyes and looking over him carefully. Without worrying about a fight, he could appreciate the other’s strange, but beautiful form. The color of his skin reminded him of the sea’s color just as the sunset gave way to night. "I’ve been alone for quite a while. And you seem to be just as alone and _perhaps_ I’d be willing to accept your company. I’ve got many sharks that stalk the waters, real jerks. You're free to help yourself."

It had to be a sight, Loki hunting predators that were usually at the top of the food chain. 

"No strings attached? You would let me into your home?" The offer was tempting, but still threw Loki off, he had been looking for answers and he had them. He could depart now satisfied, but that wasn't appealing any longer. He did not have to play brave in his game for answers as they had come rather painlessly from the source with a little prompting. 

Yet, Loki felt wrong finned, not at all used to friendly contact. He felt almost physically overwhelmed by the notion of going against the solitary, nomadic lifestyle of his kind. Was unable to stop himself from flinching back, finally breaking their hands apart when he felt Tony's tail brush against his own. He was examining his potential host, noting the slight lines around his eyes, the scars scattered across his flesh and tail, and groomed facial hair. It was a feature that Loki had also seen the Aesir mers sporting but did not exist on Jotun. 

The mers of the deep had to be quick to catch their prey in the darkness that seemed to swallow all. Perhaps they had evolved to be more hairless to achieve less drag in the water, their tails streamlined for speed. Still, that was neither here nor there. Loki could tell that Tony surpassed him by a notable number of years, had knowledge of the water above the chasms that Loki craved. 

Tony was disappointed as they broke apart, but he stayed in his spot trying to appear casual and not at all desperate now for the chance of company that was dangling before his eyes. He shrugged, playing it cool as he attempted to charm the other mer. "I assume it's that or you try and eat me again. I would not like that by the way. I would rather be a friendly face to you." He licked his lips again and gestured. "I have a little cave and kelp bed made here. If you like, I could make you one."

Tony was trying to rein his seahorses in, but was finding it increasingly difficult as his body craved for the contact of another once more. 

"Well I've decided that you'd probably be too spicy and stringy, but I suppose I could spend a bit of time here. I have nothing better to do." Loki answered, nodding for the other to lead the way. The concept of sleeping in a cave or with bedding in general, was a foreign one. Jotuns constantly drifted from place to place in the deep, buried themselves deep under the course, cold sand when they did decide to rest. As he followed the golden tailed male, Loki watched curiously as the landscape around them grew steadily different as they moved closer to the volcanic vents.

The heat, Loki thought that he _should_ be finding it uncomfortable, but it seemed that his body was quickly growing used to it. His throat burned a little as his gills were unfamiliar with what they now had to filter. 

Tony led him through the sharp cooled volcanic rocks, looking back once in a while before poking himself into his own cave. It wasn’t exactly hidden either as Tony had spent quite a bit of time collecting and then melting the shiny pieces of metal he found from nearby shipwrecks along the opening. It glittered under the sunlight through the waves. Flashy and obvious… much like the owner. The creatures around here knew who the mer was, a threat on his own and left alone. 

It would barely hold the both of them, a tight fit but Tony smiled as he patted over the thick woven mats of kelp that covered the bottom of the cave. "See? Casa la Stark, I could make you something like this."

The other mer hesitated at the opening of the cave, the space was small and being in a cramped hole with another was unfamiliar water to him. Slowly, Loki eased his long tail into the cavern. It may have been that Tony overestimated the amount of space that was inside of his home as they fumbled against each other for space and a comfortable position. In the end, Loki ended up having to wrap his tail around the golden one. A dark purple flush upon his cheeks as only a scant few inches separated their torsos.

Tony was warm, from the tip of the tail up he radiated heat that had Loki's cool body shivering. 

"Perhaps, this wasn't the most clever of ideas." Loki muttered under his breath, yet made no move to actually get more room between them. 

Tony swallowed and nodded in agreement as he looked between them. Those horns on the top of Loki’s head, they were glowing again, the golden light they produced lit up the small space. Not that Tony needed any light as he had been living in this cave for years, he knew every nook and cranny of the place. Had decorated it with knickknacks he had found over the years from the many wrecks, things dropped from above or brought with the ever-flowing currents. Many twinkling, strange things lined the shelves Tony had carved out. Strung up with thin strips of kelp, yet more hung from the ceiling of the cave.

With barely any space between them, the feeling of scales against his own, Tony’s thoughts felt a little fuzzy. So close, Loki’s scent was invading his nose: sharp, metallic, if cold had a scent it’d be Loki’s. Tony knew that his own scent had a slightly sulfuric quality to it from his life near the vents and the fire running through his veins. Sweet Salacia, it was mating season for his kind wasn’t it? He’d been alone for so long; he’d almost forgotten the urge. 

He tried to bury it down since he reached maturity, afraid that his excitement would end up scalding his partner. Not that anyone was interested in taking such a risk, Tony’s personality wasn’t exactly the most desirable either. Always trying to take things apart, tinkering with the items he found from above that scared the rest of his species, and his charm was at times overridden by his temper.

Loki seemed to care little about any of this. Those red eyes had glanced around his cave and collection of treasures with wonder. Seemed to hunger for knowledge as much as Tony and even had that habit of putting himself in danger to get the answers he wanted. He had no way of knowing if they were a possible match biologically, but by the seven seas, Tony hoped that they might be.

These thoughts were all consuming, until he felt himself closing what little space they had and pressing his mouth to Loki’s gently. Asking as they drew apart with a smirk, his tail skating around Loki’s and reaching out to touch his sides, scales, and those delightfully artistic raised lines that covered his skin. "Are you sure about that?"

A trilling sort of sound left the deep sea mer's mouth at the touch of the other's lips upon his, red eyes widening in both confusion and alarm. The feeling of Tony's own claw tipped fingers trailing over his flesh were setting fires under Loki's skin. Back against the kelp mats which laid upon the smooth rock of the bottom of the cave, worn by the many years that it was Tony's residence, Loki shuddered. The pelvic fins that had been tucked tight to his waist and tail to slide into the cave were being brushed over by Tony's own bright red pelvic fins, long smooth strokes trying to urge those dark green one's apart.

Obviously, Tony had been lonely for a long time, while Loki wasn't opposed to the idea with the threat of being eaten after mating off the table, he wasn't exactly experienced. 

Tony tipped his head when Loki didn’t reply. _Shit_ , had he fucked up? How many cultural difference existed between them? Loki, with that young, foreign face looked so shocked it almost pained Tony.

He didn’t want to scare Loki off, he moved his hands away from lightly scratching at the longer mer’s ribs to rest on his shoulders. "We can leave if you want." He shrugged, trying to stay in contact. "Or we could just lay here... close?" Loki was colder than him sure, but it felt nice on his scales and skin. He didn’t want to leave. Didn’t want to watch Loki flee back to where he came from. 

Did not want to be left alone again.

"I, well..." Loki struggled to put the feelings and thoughts into words as they whirled through his head. Distracted by the fact that Tony was just so _warm_. The heat sunk deep into his bones and his tail curled tighter around the shorter one in its multiple loops at the idea of parting. "It's not that I'm... disagreeable. More that I wonder if we are compatible?"

How each of their bodies worked was a mystery to each other, they had obvious physical differences. What laid under scales and skin was unknown, but Neptune be damned if Loki wasn't craving to find out.

"It's also that I'm not exactly experienced, it's not very appealing an idea to mate if there is a high chance you become dinner afterwards. Neither is it usually gentle." All of Tony's actions were light, testing, but eager certainly. There was no wash of blood in the water with screeching, clawing, and biting that ended relatively quickly. Loki had only dared to watch a few matings from a distance. He never meant to, more that he accidentally stumbled upon the affairs when chasing prey that was attracted to the scent of blood.

Brown eyes widened, surprised that the other hadn’t at least played with another of his kind like it was common for Tony’s. If there was a threat of death, that meant that Jotun usually took multiple mates in their lives. He shook his head, trying to reassure, "I have no desire to eat you when we’re done. Usually a mate’s someone for life, like in _actual_ mating. Not just, ya know, rubbing tails off."

Which Tony found himself really hoping for as he purred. Settling his forehead against his relishing the way that Loki held him tight. He moved his hands again, now rubbing small circles on Loki’s sides, thumbs brushing both flesh and scales in one motion. "I’d be willing to teach you."

"For _life_?" Loki echoed, the words were daunting ones and should have one of his kind swimming for the chasms, they had multitudes of partners in their lives if they were lucky enough to not end up being the nutrition for their just conceived spawn. There was also the fact that they had only just met a few hours ago. Yet Tony was willing to tie himself to him? 

Was the volcanic mer that desperate to keep his company? They fascinated each other, outcasts from their kind, and wishing for something new.

Something interesting.

Something crazy and certainly made of bad decisions as they were both apparently impulsive creatures.

"I _suppose_ that that doesn't sound too bad." Loki finally answered, purple still staining his cheeks as his fins finally gave into the prompting of Tony's, lifting up and away in their still admittedly limited space.

Tony cuddled further into him and chirped softly, his arms wrapping around Loki testing the waters as it were. Not wanting to move too fast or suddenly despite how his pelvic fins had minds of their own. "Do you want a bigger nest? Or does this work for you?"

"For now, it will do, but I doubt we will be comfortable here for too long when I can't even stretch my tail out." Loki's breath was coming out in short puffs, swirling the water. Trying to relax into the close contact, despite it being so difficult as his mind and body argued about its meaning. His own fingers, careful of their claws drifted over the other's shoulders, running over the golden scales that dotted them before moving towards that impressive sail that had entranced him.

Tony nodded and purred against him peppering kisses along his jaw. "We can make a new nest somewhere tomorrow then."

 _We_ , it was such a surprising word, but Loki found himself distracted from dissecting it as he felt the other's searing lips upon his skin, teeth worrying skin that had soft trilling noises leaving the Jotun's mouth. The softer, but still present spines inside of Tony's pelvic fins were lightly scraping along Loki's hips and the beginning of his tail in a way that had Loki out of breath.

Tony smiled, continuing to meld them closer, oh he felt that he wanted to melt over Loki. Continuing to leave kisses anywhere he could reach, he muttered. "You feel good against me." It was so difficult for Tony to remain still, constantly shifting and fingers examining flesh that felt tougher, tighter than his own, "What's on your mind?"

"Far, _far,_ too much I assure you, it's a curse I have." Loki answered, eyes falling closed as he urged himself to… Well, not exactly to relax, but to let these new sensations take him. "You're... the heat feels..." He wasn't sure how to exactly describe it as his body sucked up what it had only recently come to know. Feeling the other's pelvic fins tapping where flesh and scales met had him crooning, "I believe it is not so hard to figure out what is on _your_ mind."

Tony chuckled softly and purred against him. "I believe you’re right, quite difficult not to think of anything else when you’re with one so beautiful."

The compliment had another chirp leaving Loki's lips, even as he rolled his eyes at the line. Still shuddering as he felt the brushing of even hotter water against his face and neck. The source, the constant recycling of water through Tony's gills, which were pressed close to him as Tony nuzzled and nipped at Loki's own gills. The water was already warm around them, but after moving through the volcanic mer's body it grew yet warmer before being released.

Loki's thumbs moved along either side of the impressive sail on Tony's back while the other mer's fingers trailed along the front of Loki's tail, edging, teasing the long slit there open. Exposing the slender tentacle like penis that was common among all merkind, just far bluer. A finger's length lower from where it emerged, was the opening to his channel.

Tony looked down with a smile his tongue moving over his own sharp teeth as his breaths slowed and his fingers trailed closer to their goal. "Just, just tell me when you would like to stop." He hoped that if the other did call for a halt that Tony could actually make himself do it, he hummed appreciatively as the sight of the length. 

His fingers teasing softly over the tentacle. Letting it wrap itself around his digits as he ran a thumb along the sides of it. "Fuck, you’re gorgeous."

The longer mer growled as he rocked his hips into the hold the other had him, "If you stop, I believe I'll be _more_ likely to gut you than I was when I was trying to _eat_ you." Now his claws were worrying the thin flesh between each of the spines, a silent assurance that he would do just that if Tony decided to test his luck.

Tony moaned as he teased his own red flushed tendril against Loki’s, he tried to pace himself but if Loki really didn’t want him to… A surprised chirp left his lips that was mixed with a hiss of pain as Loki leaned forward to dig his teeth into Tony’s shoulder. Ouch, that stung, but the feel of the cool tongue moving over the wound to sooth it was fantastic. He could hope that Loki wasn’t going to change his mind about not making Tony a snack. 

At the same time, Tony thought that he would probably feel pretty insulted if Loki said he tasted gross.

"I want to be inside you, may I?" Tony asked breathy as he pressed a kiss against the base of Loki’s horns, his temples, all that he could reach as Loki had finally released his shoulder from his teeth. This would be the last chance that the younger would have to back out of actually mating. His hips quivered and tail twitched in the loops of Loki’s tail. 

Loki shuddered, his own croon echoing Tony's as their lengths wrapped and twisted together. Neither had true control of their own tendrils that searched for pleasure. The taste of Tony’s blood was indeed spicy in a way that it made Loki’s whole tongue feel like it was tingling. Yet another source of heat that Loki desperately wanted more. 

He wanted _all_ of Tony. The sound he made, Tony took as confirmation. As Loki felt fingers probing their way inside of his mating channel for the first time it caused Loki to throw his head back.

His claws were soon digging into the other's back though, when all that those fingers were doing was rubbing and stretching apart, causing Loki to demand, “By the Charybdis, I may be inexperienced, but I am not delicate!"

“No, you’re impatient,” Tony groaned out, Loki’s channel felt cool against his fingers, but not unpleasant. It made him ache to be inside of it. Keeping his fingers inside of the slit he parted it as much as possible before shifting his hips down, a difficult task when Loki’s tail had a vice like grip on his own. Both whined at the loss as the distance forced their lengths apart. Tony’s searched for a new source of pleasure, twisting itself over the skin of Loki’s belly, hips, and then finally it found the hole that Tony’s fingers were keeping open.

Tony crooned at the feeling of the tight channel locking around him, forcing out water. Loki on the other hand almost howled as he felt the stretch and movement inside of him. His mind stuttering at the additional feeling of a mouth working down Loki's neck. 

The feeling of the other's teeth nipping his gill flaps had Loki tensing, knowing that if the other bit down too hard the damage would be catastrophic. It made him want to flee, to fight, to protect himself, yet Loki did none of those things as he felt Tony's length snug inside him. It was too large, it had to be. Maybe nature dictated that they were not meant to fit together after all. 

With every moment that passed, it slowly got better and Loki keened at the feeling. The warmth spreading from the inside out. His instincts gave him no chance to rest or adjust, they had him giving a sharp buck, gasping as he felt the squirming tendril sink even deeper inside.

Tony moaned against him and chirped as his own tail moved to fuck himself slowly into Loki. He leaned down to try to capture his lips in another kiss. He was honestly pretty sure that the entire ocean could hear them, yet he didn’t give a flying fish of a fuck as he muttered between reassuring kisss to the shivering body under him. "You feel so good, oh wow."

While having no previous experience in kissing, Loki was proving himself to be a fast learner, copying the way that Tony twirled his tongue with his own, but the unfamiliarity with the shape of each other’s mouths and teeth led them to nicking each other from time to time. The sting spurring Loki on as he gasped into the kiss, rocking his hips to meet his mate’s thrust. His own length squirmed between their bellies, the tight hold they had on each other creating delicious friction against it. “I wonder,” he managed to bite out, “if this is what it feels like to be filled by a volcano. You,” a yelp interrupted Loki as he felt the squirming length press unimaginably deeper, “-will fill me, won’t you? Tony.”

They both were desperate for it. 

Tony moaned at the way the other had said his name in a low rumble of sex. It sounded absolutely divine. If he could trade the crash of the waves for Loki’s voice, he’d do it in a heartbeat. He twisted their intertwined tails so that Loki’s was lifted completely off of the kelp mats, giving Tony the grip and traction to move faster, harder. He could hear himself babbling, but who cared? Loki didn’t seem to, as the younger mer let out such pretty noises with each compliment and promise. "Yes, oh fuck yes I'm gonna fill you, fuck, you feel so amazing." 

He had his head on Loki’s shoulder as he focused on the movement between them. His hands were never still as he stroked what he assumed was the flesh that was as sensitive as his own where skin melded with scales. From the way Loki responded, he had guessed right. 

What was incredible was the fact that Loki was chilly on the inside, but everytime Tony moved it would warm and then chill once more, it felt phenomenal.

From his earlier demands for roughness, Loki seemed to be finally receiving what he wanted. Almost _too_ , too much as his muscles continued to burn from the stretch inside of him and the unfamiliar arch his body bent itself into in an effort to get that minuscule amount closer to the golden mer. It felt like there was not even a barnacle’s worth of space between them in some places. They were drifting towards some sort of chasm as Loki swore that something inside of him was about to snap. 

Loki's claws raked down Tony's back on either side of where the sail emerged. The specialized dorsal fin rising steadily as he did so, swaying in the water with the rocking of their bodies. The soft light that was being produced from Loki's horns dancing off of the many shiny trinkets in Tony's cave and across their flashing scales.

Tony gasped and chirped, some other noises escaping his lips as he rocked and moved inside of Loki moaning lowly. He was close, oh he knew it and he gripped the other mer tighter his hands shaking. About to take a mate, to claim Loki as his own. It was a heady thought, "Oh Loki, oh by Poseidon, I'm so close now."

For a brief moment, Loki felt fear rolling back up his spine at the declaration. How would it feel like inside of him? What would it be like to be tied to Tony forever as mates? Should he try to buck the other out and off to escape? These were only fleeting half formed terrors that really only existed as a whisper in the back of his mind. He kindly told them to go dance with a giant squid rather than haunt him when he had felt more alive than he had since hatching. He quivered at how hot and deep Tony was. With the tight, grounding hold around him, Loki wasn't likely to be going anywhere anyway. 

"Tony, ah," Loki almost felt sick with pleasure as he teetered on his peak, felt the other's hand slip between their bodies. Claws lightly scratching at his belly before Loki's length squirmed into Tony's fingers. 

In that moment, Loki completely came undone, keening as he released into the water and his channel.

Tony moaned as Loki shook beneath him clutching to the deep sea mer as he let himself lose control and release himself into the other. Moaning and panting against him as his tail stayed wound tight around the other keeping him anchored in that wonderful little cavern that was now the only one for Tony. For the moment all he could do was shiver against him. "Oh Loki, _mine_."

 _Mine_ , the declaration had a thrill running through Loki's already taxed spine and he growled back as he gave a nip to Tony's ear, "Mine." He echoed the sentiment and felt it doubtlessly true. 

The mere idea of tangling tails with another was repulsive and imagining Tony doing the same had his teeth gnashing. He’d eat any that would dare trespass on what was now his. Loki had been ruined from following in the tail streams of his species, but he didn't care. As he felt the other's release inside of him, hot and heavy, almost making him feel like he was cramping with the amount stretching his stomach taunt. 

Loki realized that he loved it. In the deep where food was scarce, they were made to eat as much as possible in one sitting, but how he felt now... It was far more satisfying than being filled in a different way. 

Loki hummed against the volcanic mer's neck, mumbling as he lapped at his gill flaps, neither in a hurry to part or move. Not that they could as Loki's channel was locked tight around Tony's still twitching length, would be for a bit of time. He mused, wondering how the other might react. "Do you think you spawned me?"

Tony growled low in his throat at the words and only wanted them to be partly true. Spawn, that was something he had never considered. Never thought it possible with his curse. He kissed Loki's shoulder and purred, the cool tightness of Loki's channel calming, as was relaxing with the larger predator. What a weird turn his life had once again taken. "If I had it would be a wonderful conception." He smiled a toothy grin and looked to the red eyes of the other mer. "What do you think? My own _mate_? Did you receive my spawn?"

"It is too early for me to tell, you fool." Loki could not help but roll his eyes, Tony's ego was apparently full of hot water as much of the rest of his body. The idea of himself swollen with spawn, the mystery of what the life created between them might look like was unfathomable. Could they swim hot like the father, cold like the bearer? What might their tail or skin look like? Was it even possible that Loki could take Tony's seed or carry it to laying? Could it even hatch here or would they have to move somewhere else? 

Too many possibilities, yet as he examined the other's gaze, he found only affection, wonder, and pride that Loki had so rarely received before.

Loki knew that they would find out together. 

"Let us hope that they come out temperate, I do not know if the ocean could take another of either of us." Loki mused as he caught the other's lips in a kiss, eager for more of them as his exhausted body urged him towards sleep.

Tony kissed him back in return his hands smoothing over him as he nodded and closes his eyes. "Let’s just pack it in for now, I’ll gather you food in the mornin’."

Loki gave a tired snicker, feeling that he might melt between the soft mat and the heat his mate provided, "So you will be feeding me after all? You don't even know if..." A yawn interrupted him, he had swum leagues upon leagues the past few days, never truly able to relax in such a foreign environment with unknown dangers. Now, with Tony petting over his full stomach and tail held in a way that echoed how his own bearer would to assure that he would not drift away in his sleep, Loki was losing the battle to stay awake. 

He was no invalid, he could hunt and fight for himself, had done exactly that to _Tony_ earlier; but that could wait for later. He tucked his head in the crook of the older mer's neck and shoulder.

Relaxed by the steady beat of the other's heart against his own along with the flow of water from Tony's gills over his face, Loki smirked as he made a final sleepy demand before giving into the embrace of sleep, "I want those weird puffing spiky fish."

The grumbled complaint that followed him into dreams was quite the delight. 

* * *

Notes:

Salacia- Neptune’s consort

Neptune -ancient Roman name of the Greek god of the sea and earthquakes, Poseidon

Charybdis- a Greek sea monster and spirit of whirlpools and the tide.

**Author's Note:**

> This was based off of a roleplay with ladyexy and edited by my wonderful beta Rou.
> 
> Hope you all enjoyed it, this was my first stab at writing anything mer related and we might play around with this story again in the future to make a series from it following Loki and Tony making a pod with old and new faces. 
> 
> Please tell me your thoughts? Had a favorite line or scene? I'd love to any them.


End file.
